Question

A sample of mono-atomic ideal gas is taken through a cyclic process ABCDA. A graph is plotted in which heat exchanged by the gas upto an instant is shown on x - axis and work done by the gas upto that instant is shown on y - axis.


The given cyclic process can be represented on a pressure - volume graph as

• A.
• B.
• C.
• D.

Answer 1

The correct option is A

From the figure given in the question, we can deduce that,
For process $AB,\Delta Q\ne 0,\Delta W=0$
and for process $CD,\Delta Q\ne 0,\Delta W=0$
$\therefore$ process $AB$ and $CD$ are isochoric
For process $BC,\Delta Q=\Delta W=400\text{J}$
and for process $DA$, $\Delta Q=\Delta W=-400\text{J}$
$\Rightarrow \Delta U=0$
$\therefore$ process $BC$ and $DA$ are isothermal.

Hence, the $P-V$ graph equivalent to the given graph is